Polyolefins stabilized with organic hydrazine compounds and phenolic antioxidants

ABSTRACT

ALKYLHYDROXYPHENYLALKANOYLHYDRAZINES OR ALKYLHYDROXYBENZOYLHYDRAZINES AND PHENOLIC ANTIOXIDANTS STABILIZED OLEFIN POLYMERS IN THE PRSENCE OF METALS.

ni ed tm sPa mrO ii 3,772,245 POLYOLEFINS STABILIZED WITH ORGANIC HYDRAZINE COMPOUNDS AND PHENOLIC ANTIOXIDANTS Martin Dexter, Briarclitf Manor, N.Y., assignor to Ciba- Geigy Corporation, Ardsley, N.Y.

No Drawing. Continuation-impart of application Ser. No. 28,048, Apr. 13, 1970, which is a continuation-in-part of application Ser. No. 811,664, Mar. 28, 1969. This appplication Mar. 8, 1972, Ser. No. 232,959

Int. Cl. C08f 45/58 U.S. Cl. 260-4535 N 15 Claims ABSTRACT OF THE DISCLOSURE Alkylhydroxyphenylalkanoylhydrazines or alkylhydroxybenzoylhydrazines and phenolic antioxidants stabi lized olefin polymers in the presence of metals.

Polymeric materials such as polyolefins normally lose their physical and electrical properties during service due to oxidative, thermal and/or ultraviolet light deterioration. In order to prolong the'life of the polymers, various stabilizers such as antioxidants and ultraviolet light absorbers are added to these polymers. In some instances, however, the polyolefins cannot be effectively stabilized even with the addition of such stabilizers. This usually occurs when the polyolefin is in contact with a metal, particularly copper, or contains within its composition certain metallic impurities. The metal may be in the form of copper wire when the polyolefin is used as a wire coating insulation or may be present as catalyst residues. In these cases, the metal acts as a catalyst for the decomposition processes and generally the stabilizers added to the polyolefins do not substantially retard this catalytic activity. The end result is that even though the stabilizers have been added, polyolefins decompose and lose their desirable physical properties sooner than expected.

The instant invention is concerned with polyolefin compositions which contain additives that act as antioxidants and/ or metal deactivators. In other words, when the additives of this invention are incorporated into polyolefin polymers, the adverse effect of the metals on the polymer is substantially checked. The metals that may be present in polyolefins or be in contact with polyolefin are iron, nickel, cobalt, manganese, titanium, vanadium, chromium and cadmium, and especially copper. The instant composition comprises an olefin polymer such as low, medium or high density polyethylene, polypropylene or copolymers thereof and copolymers of ethylene and a minor amount (up to 10%) of a higher a-olefin such as butene-l, hexene- 1, octene-l, dodecene-l and the like, stabilized with (a) An organic hydrazine compound which is an alkylhydroxyphenylalkanoylhydrazine or an alkylhydroxybenzoylhydrazine having the formula 2 wherein R is a lower alkyl group containing from 1 to 5 carbon atoms,

3,772,245 Patented Nov. 13, 1973 I R is hydrogen or a lower alkyl group containing from 1 to 5 carbon atoms,

11 is an integer from 0 to 5,

R is hydrogen, an alkanoyl group containing 2 to 18 carbon atoms, a group represented by the formula or an aroyl group having the formula wherein R and R are independently hydrogen, alkyl, alkoxy or halogen where the alkyl group has up to 18 carbon atoms and (b) A phenolic antioxidant. This composition may optionally also contain other stabilizers commonly employed by those skilled in the art such as thiosynergists, phosphites, carbon black and the like.

Illustrative examples of lower alkyl groups that are substituted on the phenyl moiety are methyl, ethyl, propyl, isopropyl, butyl, t-butyl, t-amyl and the like. The preferred groups are the tertiary alkyls. Illustrative examples of the alkyl groups having longer chain groups are hexyl, hepyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl and the like, both straight chain and branched chain. Illustrative examples of the alkanoyl groups represented by R may contain from 1 to 30 carbon atoms and preferably from 210 18 carbon atoms.

The preparation of the alkylhydroxyphenylalkanoylhydrazine compounds employed in this invention is described in the copending application Ser. No. 28,048, filed on Apr. 13, 1970, and in an application filed Mar. 1, 1972.

Illustrative examples of alkylhydroxyphenyl-alkanoylhydrazines which can be employed in the instant application are listed below:

(A) N,N'-bis-fl-{3,5-di-t butyl 4 hydroxyphenyl) propionyl}hydrazine (B) N stearoyl N'-{B-(3,5 di-t-butyl-4-hydroxyphenyl) propionyl}hydrazine (C) N a-(3 ethyl 5 t-butyl-4-hydroxyphenyl)- propionyl}-N-{B (3,5-di-t-butyl 4 hydroxyphenyl)- propionyl}hydrazine (D) N 3 (3,5 di-t butyl-4-hydroxyphenyl)propionyl}-N' (3,5 di t butyl-4-hydroxybenzoyl)hydrazme (E) N stearoyl N {/3-(3,5 diisopropyl 4hydroxyphenyD-propionyl}hydrazine (F) N stearoyl N 3 (3 methyl 5-t-amyl-4- hydroxyphenyl)propionyl}hyd-razine (G) N benzoyl N' {/3(3,5-di-tert-butyl-4-hydroxy phenyl)propionyl}hydrazine (H) N-p-dodecyloxybenzoyl-N-{fl(3,5-di-tert butyl-4- hydroxyphenyl)propionyl}hydrazine (I) N'- (2,4-dimethylbenzoyl) N {(3,5-di-tert-butyl- 4-hydroxyphenyl)propionyl}hydrazine (I) N-(2,4 dichlorobenzoyl)N'-{56,5 di-tert-butyl- 4-hydroxyphenyl)propionyl}hydrazine (K) N benzoyl N {/8-(3 methyl-5-t-butyl-4-hydroxyphenyl propionyl}hydrazine (L) N benzoyl N (3,5 di t-butyl-4-hydroxybenzoyl)hydrazine (M) N(p methylbenzoyl) N 3(3,5-di-t-butyl-4- hydroxyphenyl)propionyl}hydrazine (N) N(p ethoxybenzoyl) N {(3,5-di-t-amyl-4- hydroxyphenyl)propionyl}hydrazine 3 (O) N benzoyl N {(3,5 di t butyl 4-hydroxyphenyl) -valeryl}hydrazine Illustrative examples of phenolic antioxidants that can be employed in the compositions of this invention are listed below.

(1) Phenolic compounds having the general formula R is hydrogen or lower alkyl R is lower alkyl R is alkyl group having from 6-24 carbon atoms w is an integer from to 4.

Illustrative examples of the compounds shown above are CHz-C H 000 C isHn di-n-octadecyl a-(St-butyl-4-hydroxy-S-methylbenzyl) malonate di-n-octadecyl a-(3-t-butyl 4-hyd-roxy-5-methyl-benzyl) malonate which is disclosed in the Netherlands Patent No. 6711199, Feb. 19, 1968 di-n-octadecyl-a,abis-(3-t-butyl-4 hydroxy 5 methylbenzyl)malonate which is disclosed in the Netherlands Patent No. 3803498, Sept. 18, 1968 (2) Phenolic compounds having the general formula Illustrative examples of the compounds shown above are 2,6-di-t-butyl-p-cresol Z-methyl-4,6-di-t-butyphenol and the like (3) Phenolic compounds having the formula Q w' 2w-Q 2,2-methylene-bis(6-t-butyl-4-methylphenol) 2,2-methylene-bis(6-t-butyl-4-ethylphenol) 4,4'-butylidene-bis(2,6-di-t-butylphenol) 4,4-(2-butylidene)-bis(2-t-butyl-5-methyl- 2,2'-methylene-bis 6-( l-methylcyclohexyl) 4-methylphenol] and the like.

(4) Phenolic compounds having the formula RO-Q Illustrative examples of such compounds are 2,S-di-t-butylhydroquinone 2,-di-t-butylhydroquinone 2,6-di-t-butyl-4hydroxyanisole (5) Phenolic compounds having the formula 0 Q(CH2) s(CH2)r-( :OR"

Illustrative examples of such compounds are:

octadecyl-(3,5dimethyl-4-hydroxybenzylthio)acetate dodecyl-( 3,5 -di-t-butyl-4-hydroxybenzylthio)propionate (7) Phenolic compounds having the formula cm CHIB I CH; CI-I B wherein B B and B are hydrogen, methyl or Q, provided that when B and B are Q then B is hydrogen or methyl and when B is Q then B and B are hydrogen or methyl.

Illustrative examples of such compounds are:

1,4-di(3,5-di-t-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethyl benzene 1,3,5-tri(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene (8) Phenolic compounds having the formula ?D N N (Q) L J wherein Z is NHQ, SD or O Q D is alkyl group having from 6-l2 carbon atoms or C H )SR" Illustrative examples of such compounds are 2,4-bis-(n-octylthio)6-(3,5-di-t-butyl-4-hydroxyaniline)- 1,3,5-triazine 6- (4-hydroxy-3methyl-S-t-butylanilino -2,4-bis- (noctylthio)-1,3,5-triazine 6- (4-hydroXy-3,S-dimethylanilino) -2,4-bis- (n-octylthio 1,3,5-triazine 6-(4-hydroxy-3,S-di-t-butylanilino) -2,4-bis-(n-octy1thioethylthio)-l,3,5-triazine 6-(4-hydroxy-3,5-di-t-butylanilino)-4-(4-hydroxy-3,5-dit-butylphenoxy)-2-(n-octylthio)-1,3,5-triazine 2,4-bis(4-hydroxy-3,S-di-t-butylanilino)-6-(n-octylthio)- 1,3,5-triazine.

The above phenolic triazine stabilizers are more fully described in US. Pat. 3,255,191.

(9) Phenolic compounds having the formula wherein Z is -OQ, SD or S--(C H )SD Illustrative examples of such compounds are:

2,3-bis-(3,5-di-t-butyl-4-hydnoxyphenoxy)-6-(n-octylthio)-1,3,5-triazine 2,4,6-tris-(4-hydroxy-3,S-di-t-butylphenoxy)-1,3,5-triazine 6-(4-hydroxy-3,5-di-t-butylphenoxy)-2,4-bis- (n-octylthioethylthio) 1,3,5 triazine 6-(4-hydroxy-3-methylphenoxy)-2,4-bis-(n-octylthio)l,

3,5-triazine (13) Phenolic compounds having the formula wherein R, R and w are as defined above.

Illustrative examples of the compounds shown above are:

1,3,5-tris(3,S-di-t-butyl-4-hydroxyhydrocinnamoyl) hexahydro-s-triazine 1,3,5-tris( 3-methyl-5-t-butyl-4-hydroxyhydrocinnamoyl) hexahydro-s-triazine 1,3,5 -tris 2,5 -di-t-butyl-4-hydroxyhydrocinnamoyl) hexahydro-s-triazine The phenolic compounds preferably employed in this invention are the compounds having the formula wherein Q, R, R", p and z are defined above. The most preferred compound is pentaerithritol-tetrakis-{3-(3-5fdi-t-butyl-4'-hydroxyphenyl)propionate}.

Compositions of this invention in the concentration of from .01 to 5% by weight of the resin and more preferably from 0.05 to 1%.

In addition to the organic hydrazine compounds and antioxidants there may also be present in the compositions of this invention synergists such as dilaurylthiodi propionate or distearylthiodipropionate phosphites, thermal stabilizers, carbon black, coloring materials, dyes, pigments, buffers, and other additives that are sometimes incorporated in the polyolefins for particular reasons.

Since the oxidation of polyolefins is slow at ambient temperatures, even in the absence of stabilizers, the testing of the effects of the metal deactivators is usually accelerated by conducting the tests at higher temperatures in order to obtain results within a reasonable time. For this reason the tests described below were conducted at elevated temperatures.

Procedure for determination of thermal stability of polypropylene copolymer with imbedded copper screen TABLE I Hours to failure at- Example No. Formulation 150 0. 140 0. 120 C.

1 0.2% Compound A 150 870 870 2 0.2% Antioxidant 1 100 360 460 3 0.2% Compound A plus 0.2% 520 1,090 1 2, 240

Antioxidant 1.

4 0.2% Compound G plus 440 870 +1, 500

0.2% Antioxidant 1.

1 Refers to the lettered compunds listed above. a Test was terminated at this point.

Nora-Antioxidant 1 is pentaerythrltol tetrakis-{3-(3,5-di-t-butyl- 4-hydroxyphenyl)propionatei.

Similar stabilization obtained when Compounds A and G employed in a 0.05% concentration and Antioxidant 1 employed in a 0.1% concentration.

Similar stabilization is also obtained as shown in Table I when Compounds A and G are replaced with Compounds B, D, F, J and K and Antioxidant 1 is replaced with the following antioxidant compounds:

1,3,5-tris(3,5-di-t-butyl-4 hydroxybenzyl) s triazine- 2,4,6-(1H,3H,5H)-trione octadecyl ,e- 3,5 -di-t-butyl-4-hydroxyphenyl propionate dioctadecyl 3,S-di-t-butyl-4-hydroxybenzyl-phosphonate 2,4-bis-(n-octylthio)-6-(3-,5-di t butyl 4 hydroxyanilino)-1,3,5-triazine 2,4bis-(3,5-di-t-butyl-4-hydroxyphenoxy) 6 (-n-octylthio 1,3,5 -triazine diethyl-2,2-bis-(3',5'-di-t-butyl-4 hydroxybenzyl)malonate di-n-octadecyl-2,2-bis-(3',5'-di-t-butyl-4 hydroxybenzyl) malonate diphenyl-2,2-bis-(3,5-di t butyl 4 hydroxybenzyl) malonate The additives as indicated in Table II below were dry blended into low density polyethylene (Union Carbide DYNK-2 resin) and extruded at 450 F. The extruded material was pelletized and then re-extruded at 450 F.

onto 22 AWG untinted copper wire. Table II shows the stability of the polyethylene wire coating when ovenaged at C. The specimens were considered to have failed when dark yellow or green discoloration and/or cracking was noted.

TABLE II Hours to Example failute No. Formulation at 120 C.

5---. Unstabilized 50 6. 0 1% Antioxldant 1. 7... 0.1% Compound A plus 0.1 Antioxidant 1 1,00 8. 0.2% Compound A plus 0.2 Antioxidant 1 1, 50

Slightly poorer or better results are obtained when the concentration of Compound A is respectively 0.1% and 5%, and now specifically when the concentration of Antioxidant 1 is varied from 0.05 to 1%.

Procedure for determining effect of processing conditions Polypropylene homopolymer was dry blended with the stabilizers indicated in Table III below and extruder compounded at three different temperatures. After extrusion, 10 mil copper screen was imbedded in the polymer by compression molding at 420 F. to yield 20 mil specimens. The specimens were then oven aged at 140 C. The samples were considered as having failed on first appearance of discoloration and/or cracking. The results of this test are recorded in Table III below.

Ethylene-hexene-1 copolymer (containing about 6% of hexene-l) is formulated with 0.5% of Compound C and 1.08% of thiodiethyleneglycol-bis(3,5-di-t-butyl-4- hydroxyphenyl)propionate or 1,1,1 trimethylolethanetris-3-(3,5-di-t-butyl 4 hydroxyphenyl)propionate and copper wire coated therewith as described in the procedure for the preparation of compositions for Table II. These compositions are found to be very stable under test conditions.

The invention has been described with respect to certain preferred embodiments 'and various modifications and variations thereof will become obvious to persons skilled in the art. It is therefore to be understood that such modifications and variations are to be included within the spirit and scope of this invention.

9 What is claimed: 1. A composition of matter comprising an olefin homopolymer or copolymer and (a) from 0.01 to 5% of an organic hydrazine compound having the formula wherein R is a lower alkyl group containing from 1 to 5 carbon atoms,

R is hydrogen or a lower alkyl group containing from 1 to 5 carbon atoms,

n is an integer from to 5,

R is hydrogen, an alkanoyl group containing 2 to 18 carbon atoms, a group represented by the formula or an aroyl group having the formula wherein R and R are independently hydrogen, alkyl, alkoxy or halogen where the alkyl group has up to 18 carbon atoms, and (b) from 0.01 to 5% of a phenolic antioxidant.

2. A composition of claim 1 having: (a) from 0.05 to 1% of an organic hydrazine compound, and (b) from 0.05 to 1% of a phenolic antioxidant, 3. A composition of claim 2 wherein R and R are tertalkyl groups.

4. A composition of claim 3 wherein the phenolic antioxidant has the formula wherein R is hydrogen or a lower alkyl group, 1

R is a lower alkyl group, and

R' is a tetravalent radical selected from aliphatic hydrocarbons having from 1 to 30 carbon atoms, aliphatic mono and dithioesters having from 1 to 30 carbon atoms, and aliphatic mono and diethers having from 1 to 30 carbon atoms,

z is an integer from O to 6, and p is an integer from 2 to 4.

5. A composition of claim 4 wherein the phenolic antioxidant is pentaerithritol tetrakis-{3-(3',5'-di-t-butyl-4-hydroxyphenyl propionate} 6. A composition of claim 5 wherein the polyolefin is polyethylene, polypropylene, ethylene-propylene copolymer or higher a-olefin copolymers of ethylene.

7. A composition of claim 6 wherein the alkylhydroxyphenylalkanoyl hydrazine is N,N-bis-{/8-(3,5-di-t-butyl-4- hydroxyphenyl) propionyl}hydrazine, N-benzoyl-N'-{fl- (3,5 di-t-butyl-4-hydroxyphenyl)propionyl}hydrazine or N-stearyl N'-{;9-(3,5-di-t-butyl 4 hydroxyphenyl)propionyl}hydrazine.

8. A composition of claim 2, which consists essentially of (a) polypropylene, (b) N,N' bis {,6 (3,5 di t butyl 4 hydroxyphenyl) propionyl}hydrazine, and (c) pentaerithritol tetrakis {3 (3',5'-di-t-butyl-4-hydroxyphenyl)propionate}.

9. A composition of claim 2, which consists essentially of (a) polypropylene, (b) N-benzoyl-N'-{fi(3,5-di-t-buty1 4 hydroxyphenyl)propionyl}hydrazine and (c) pentaerithritol tetrakis-{3-(3,5-di-butyl 4 hydroxyphenyl)propionate}. 10. A composition of claim 1, which consists essentially of (a) polyethylene, (b) N,N-bis-{fl-(3,5-di-t butyl 4 hydroxyphenyl) propionyl}hydrazine and (c) pentaerithritol tetrakis-{3-(3,5'-di-butyl 4 hydroxyphenyl)propionate}. 11. A composition of claim 2, which consists essentially of (a) polyethylene, (b) N-benzoyl-N-{B(3,5-di-t-butyl 4 hydroxyphenyl)propiony1}hydrazine, and (c) pentaerithritol tetrakis-{3-(3,5'-di-butyl 4' hydroxyphenyl)propionate}. 12. A composition of claim 2, which consists essential- 1y of (a) ethylene-propylene copolymer, (b) N,N'-bis-{B-(3,5-di-t butyl 4 hydroxyphenyl) propionyl}hydrazine, and (c) pentaerithritol tetrakis-{3-(3',5-di-butyl 4' hydroxyphenyl)propionate}. 13. A composition of claim 2, which consists essentially of (a) ethylene-propylene copolymer,

(b) N-benzoyl-N'-{ 8(3,5-di-t-butyl 4 hydroxyphenyl)propionyl}hydrazine, and (c) pentaerithritol tetrakis-{3-(3,5-di-butyl 4 hydroxyphenyl)propionate}. 14. A composition of claim 2, which consists essentially of (a) a copolymer of ethylene and hexene-1 wherein hexene constitutes less than 10% of the copolymer, (b) N,N'-bis-{,8-(3,5-di-t butyl 4 hydroxyphenyl) propionyl}hydrazine, and (c) pentaerithritol tetrakis-{3-(3,5'-di-butyl 4' hydroxyphenyl)propionate}. 15. A composition of claim 2, which consists essentially of (a) a copolymer of ethylene and hexene-1 wherein hexene constitutes less than 10% of the copolymer, (b) N-benzoyl-N-{B(3,5-di-t-buty1 4 hydroxyphenyl) propionyl}hydrazine, and (c) pentaerithritol tetrakis-{3-(3',5'-di-butyl 4' hydroxyphenyl)propionate}.

References Cited UNITED STATES PATENTS 3,538,046 11/1970 Oertel et al 260-459 NC 3,489,684 l/ 1970 OShea 2S2-403 DONALD E. CZAJA, Primary Examiner M. I. WELSH, Assistant Examiner U.S. Cl. X.R.

260-45] P, 45.7 R, 45.85 S, 45.85 P, 45.85 B, 45.9 NC, 459 R Disclaimer 3,772,245.Ma7tin Pewter, Briarcliff Manor, N.Y. POLYOLEFINS STA- BILIZED WITH ORGANIC HYDRAZINE COMPOUNDS AND PHENOLIO ANTIOXIDANTS. Patent dated Nov. 13 1973. Disclaimer filed J an. 21, 1974, by the assignee, Cz'ba-Geigy dorpomtz'on. Hereby enters this disclaimer to claim 1 of said patent.

[Ofiicz'al Gazette July 8, 1.975.] 

